#include <cstdio>

int main(int argc, char **argv) {
  int arr[] = {1, 2, 3, 4, 5};
  printf("第三个元素是 %d\n", arr[2]);
  arr[2] = 100;
  printf("第三个元素是 %d\n", arr[2]);

  return 0;
}
